Every internal combustion engine needs an exhausting valve. This valve regulates the time at which the combustion gas exits the engine's cylinder. There are several exhausting valve designs for each engine, depending on the type of engine used, on the use assigned to the engine, etc. Basically, an exhausting valve comprises a valve head for closing the cylinder exhausting outlet, and a valve body coupled to operating means for opening and closing said valve. Said operating means usually comprises cams, cams shaft, springs and valve seats, said cam shaft is engaged to the engine, said cam works on valve body for opening said valve, and said spring regulates the linear movement of the valve body.
In the particular case of motorcycle engines, a difference between two-stroke engines and four-stroke engines should be pointed out. Four-stroke engines have a structure similar to automobile's engines, but the two-stroke engines differs due to the cycle's characteristics. Even when in general terms every internal combustion engine includes the above cited means, in this particular case of motorcycle engines the exhausting system is defined by particular features. For example, the gas exhausting system includes two valve bodies connected to regulating means for opening said valve once the engine reaches a predetermined number of revolutions per minute (rpm). That is said valve bodies are closed due to the closing force applied by springs included in said regulating means, once the engines shaft reaches a predetermined number of revolutions per minute (5000 rpm for example) the cylinder internal pressure overcome said spring force and the valve bodies are opened. In accordance with the applicant's knowledge the are no regulating means for controlling the above cited force applied by the springs to the valve body. Engine manufacturers preset the valve arrangement and this feature cannot be regulated or controlled by user.
Therefore there is a market need for an improvement in motorcycle engines through which the force applied to the valve's body can be regulated by the user without specialists help, since said regulation improves the engine's performance as it will be demonstrated below.